Method of carroting prefelted uncarroted cones



Patented. Aug. 14, 1956 METHOD OF 'CARROTING- PREFELTED UNCARROTED CONES Egon EIiid, Badenweiler, Germany No Drawing. Application August 22, 1952, Serial No. 305,921

Claims priority, application Germany August 8, 1950 3 Claims. (Cl. 8-112) The invention relates to the manufacture of bat bodies from fur fibers, particularly hare and rabbit fur.

In my copending application for patent, Serial No. 240,434, filed August 4, 1951, now abandoned, of which tis application is a continuation-in-part, I have pointed: out that the preparation of bat furs was generally carried out heretofore in such a manner that the air-dried hare or rabbit skins were slightly moistened on the flash side, evenly stretched, placed on a table andthen brushed over on the hair side with the carroting agent. Hereby about one-third of the hair length, measured from the tip of the hair, was reached by the carroting agent. Subsequently, the carroted skins were dried at temperatures of about 50 to at most 70 C. After cooling, and, if necessary, a short storage the skins were again moistened at the flesh side, and the fur was shorn oif by cutting machines. For the manufacture of bat bodies, the fur was cleanedin. a blowing device and then passed in measured amounts of, for instance 90-120 g. each to the forming machine. In this machine, the fur fibers were held suspended in air and sucked, by means of an aspirating device, onto a revolving perforated metal cone in such a way that a uniform fur layer conforming to the cone was produced. The thus obtained form was then brought to a certain cohesion by spraying with hot water, so as to allow that after opening the forming machine and turning ofi the vacuum, the cone couldbe withdrawn and the conical for structure could be removed thererfom. These fur structures were then enveloped in a cloth and slightly felted. By further felting and subsequent planking, the structures were gradually densified' and converted into hat bodies under shrinking.

I have further set forth in said copending application that attempts had been made for many years to do without the complicated, time-consuming and expensive carroting of the fur by brushing the carroting agent on the fiir, and to omit the operations associated therewith. Particular attention was given to the development of methods to shear the fur fibers in the uncarroted state from the skins and to carrot the fibers by immersing the same in the carroting solution, centrifuging and drying. I have pointed out that the fur fibers treated over their whole length with the carroting agent proved to be not well suited for the manufacture of hats. In general, they could be used only in mixture with normally carroted fur, i. e. with fur where the carroting agent had been applied to the fur fibers while still upon the skin.

The invention of my copending application, Ser. No. 240,434, is based on the discovery that the hereinabove recited dificulties are overcome by using, instead of the conventional carroting solutions containing acid or oxidizing agents which affect the hair keratins oxidatively and hydrolytically, certain other carroting agents, such as thioglycolic acid, sodium bisulfite or the sodium salt of oxymethanesulfinic acid, which act as reducing agents and are capable of acting on the cystine linkages of the hair keratins so as to improve the felting properties of the fur fibers. The process claimed in said prior application consists in removing the hair or rabbit fur fibers from the skin and immersing the sham fibers completely over their whole length in an aqueous solution of the above recited compounds, which solution has a pH not exceeding 3; The thus obtained carroted fur fibers have excellent felting properties and can be used for the manufacture of hat bodies without the admixture of fibers which have been hand-carroted on the skin.

According to the illustrative examples given in my prior patent application Ser. No. 240,434, filed August 4, 1951, the uncarroted fur fibers are removed from the skin, cleaned and evenly distributed by blowing; then they are formed in the forming machine to a cone. The formed sheet of fur is sprayed with hot water, which may be acidified, and the excess of impregnating liquid is removed by suction. Subsequently, the cones are enveloped in linen cloth, slightly felted and immersed in the carroting solution, preferably with agitation of the liquid. The carroting solution may be a 2% thioglycolic acid having a pH of about 2.1-2.2 and a temperature of 40-50 C., in which case the immersion time is about 2 hours; when a 3% or 4% sodium bisulfite solution with a pH of about 3 is used at a temperature of about 7080 C., the treatment may be carried out in the former case within 1-2 hours, or the latter case within 30*60 mins. Subsequently, the fur fibers are centrifuged, if necessary rinsed with water, and processed in the usual manner. In the last stage of planking, a detergent, for instance a sulfated or sulfonated oil or fat, or a fatty alcohol sulfonate or the like, may be added to ensure the desired pithy feeling of the obtained for product.

My further investigations have shown that the process may also be carried out with the conventional oxidatively' and hydrolytically acting carroting agents, such as nitric acid solutions of mercuric nitrate, solutions containing nitric acid, hydrogen peroxide and multivalent metal salts, or nitric acid solutions of hydrogen peroxide, and the like. If these conventional carroting soiunons are employed at a lower acid concentration than heretofore, excellent results are obtained. This success is all the more surprising as heretofore all attempts have failed to carrot fur fibers which had been shorn in the uncarroted state over their whole length by a pot-carroting process and to work up. the thus treated; fibers to bat bodies.

The invention is carried out in such. a way that the. skins are depilated under omission of the heretofore used carroting procedure, that the uncarroted fur fibers are converted to cones without previous immersion, and that these cones, preferably after slight prefelting, are placed in the carroting solution and retained therein for a time sufficient to produce the desired carroting effect. The new process is, therefore, a kind of pot-carroting process, which, however, is not applied to the uncarroted loose fur fibers but to the cones which are obtained from such uncarroted fur fibers and are preferably slightly prefelted.

The uncarroted fur fibers are converted to cones in the manner set forth hereinabove and in my copending application, Ser. No. 240,434. These cones are then immersed in a conventional carroting solution of the type recited hereinbefore, but of an acid concentration which is considerably lower than the concentrations of 3-5 used heretofore, for instance which contains 0.25 to 2.5 per cent by weight of nitric acid. If hydrogen peroxide containing carroting solutions are used, the hydrogen peroxide content, which was heretofore about 543 per cent, can also be considerably reduced, for instance to about 0.5 to 2.5 per cent.

A suitable carroting solution according to the invention contains, for instance, about 1.5 per cent of H202 and about 0.3 per cent of acid. When such carroting solutions are used, the cone-liquor ratio by weight may be in the range of about 1:30 to about 1:50. The cones can quasi the acid act during the whole immersion time homogeneously on the fur fibers, which is of advantage.

It is possible to carry out the process at any desired temperature, if the most'favorable reaction time has been previously determined for such temperature by a preliminary test. At a temperature of 80 C., a carroting time of about 1-2 hours is generally sufficient. At temperatures of about 40-50 C. I prefer to leave the prefelted cones overnight in the carroting solution. However, it is also possible to impregnate the cones with the carroting solution, remove the excess of the solution, allow the impregnated cones to lie about 40 hours and to work up the cones subsequently. Another modification of my process consists in impregnating the cones with the carroting solution, removing the excess carroting solution, allowing the cones to lie for about 1-2 hours at room temperature, and then continuing the procedure for about 3060 mins. at a temperature of about 80 C. By this heat treatment, the reaction between the effective components of the carroting solution and the hair proteins is continued while simultaneously drying of the cones takes place.

The following examples are given to illustrate some embodiments of the invention but are not to be considered as limiting the invention in any way.

Example 1 Uncarroted hare or rabbit fur fibers shorn from the skins are cleaned in the blowing machine and mixed. About each 100 g. of the fiber mixture are formed to cones in the forming machine and moistened withhot water. The structures are removed from the metal cones, several structures are wrapped in one cloth, centrifuged to remove the excess water, acidified by spraying with dilute acid and prefelted to such a degree that the structures may be readily handled without injury. The cones are then immersed in an aqueous solution which contains about 1 per cent of HNO3 and 0.8 per cent of H202. After the cones have been homogenously impregnated with the solution, they are centrifuged or squeezed to remove the excess of carroting solution and allowed to stand about 40 hours at the ambient temperature. Subsequently they are worked up to hat bodies in the usual manner.

Example 2 Fur fiber cones obtained as described in the preceding examples are impregnated with a conventional carroting agent used in the hat industry in very dilute solution. The excess amount of carroting solution is removed by squeezing or centrifuging and the cones are then allowed to stand for a short time, for instance about 1 to 2 hours, at room temperature and are then kept for about 30 to mins. at elevated temperature, for instance at about C. Subsequently, the cones are worked up to hat bodies in the usual manner.

Besides solutions of acids also solutions, which contain 1 to 2.5% urea nitrate and, if it is desired, an admixture of hydrogen peroxide, may be used.

Preferably the cones, which consist of uncarroted fur fibers and are formed by the forming-machine, are moistened with hot water or with hot acidified water, and having been removed from the machine they are with advantage slightly prefelted and thereafter impregnated with carroting agents. In the most preferred manner the cones are moistened in the forming-machine with hot water, and after having been removed, they are enveloped in linen cloth and slightly felted. The unrolled cones are then moistened with diluted acid, again enveloped, while the felting process is continued, and finally impregnated with carroting agents.

The acidified water may have a pH of about 2 to 3.

What I claim is:

l. The method of pot carroting loose hare or rabbit fibers comprising immersing prefelted cones of said uncarroted fibers in an aqueous carroting solution containing as sole carroting agents about 0.5 to 2.5 per cent by weight of hydrogen peroxide and about 0.25 to 2.5 per cent by weight of nitric acid.

2. The pot carroting method claim in claim 1, wherein the cone-liquor ratio by weight is about 1:30 to 1:50.

3. The method of pot-carroting loose hare or rabbit fibers comprising immersing prefelted cones of said uncarroted fibers in a large excess of a weakly acid aqueous hydrogen peroxide solution being free of hydrogen peroxide decomposition catalysts and containing about 0.5 to 2.5 per cent by weight of H202, the acidity of said solution corresponding to an acid content of about 0.25 to 2.5 per cent by weight of nitric acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,169,997 Fabian Aug. 22, 1939 2,411,725 Hodshon et a1 Nov. 26,1946 2,582,086 Tucker et a1 Jan. 8, 1952 FOREIGN PATENTS 323,364 Great Britain I an. 2, 1930 

1. THE METHOD OF POT CARROTING LOOSE HARE OR RABBIT FIBERS COMPRISING IMMERSING PREFELTED CONES OF SAID UNCARROTED FIBERS IN AN AQUEOUS CARROTING SOLUTION CONTAINING AS SOLE CARROTING AGENTS ABOUT 0.5 TO 2.5 PER CENT BY WEIGHT OF HYDROGEN PEROXIDE AND ABOUT 0.25 TO 2.5 PER CENT BY WEIGHT OF NITRIC ACID. 